Publishing Geospatial Data >

Page 6 of 16

Searching For Metadata

How do users find your metadata?

There are several steps in the search process.

	1.		The user sends a request for information (i.e. a query) through a discovery mechanism like the GeoConnections Discovery Portal.
	2.		The discovery mechanism sends the search query to your search server. The search query specifies the geographic area the user is interested in, the keywords the user is looking for, the desired time period, and other, more detailed criteria. The exact way in which this happens, and exactly what is sent between the discovery mechanism and your search server, is dictated by the search protocol.
	3.		Your search server searches your database for individual products matching the search criteria. To do this, your search server must translate between the language spoken in the search query and the language used to ask your database where the information about the individual product(s) is actually held.
	4.		The search results are sent back to your search server by your database. These results usually include: The number of individual products (or, more technically, database records) which matched the query criteria; A list of unique identifiers for those individual products (this could be an inventory number, product identification, or image number); The geographic location of the individual products; and Other optional information about the individual products.
	5.		Your server presents the search results to the discovery mechanism.
	6.		The discovery mechanism then interprets and reformats the results for display on the user’s browser.
“Search server” is another way to say… Multilingual multitasker! A search server both translates and “serves” questions and answers between computers. A search server must know what to look for in the database that contains the metadata. Each search server understands its own metadata format. The server has to translate between its own metadata fields and the database fields. It must also pass on (or serve) the translated query to your database and get the results of the query from the database. The search server can fulfill these roles because it is fluent in languages like Visual Basic Script (VBScript), Structured Query Language Network (SQLNet), Eiffel Structured Query Language Library (ESQL), or Open Database Connectivity (ODBC). Quick service, in different languages, for multiple “clients”: search servers definitely earn their keep!

Page 6 of 16